Hydroxyl (OH) radicals were generated by dielectric barrier discharge (DBD) from water vapor in a multi-pass cell with a volume of 8000 cm3. The cell was filled with the following water vapor at reduced pressure. The absolute OH number density was accurately determined by direct absorption spectroscopy using a tunable laser operating at 2.8 μm. The absolute OH number density was around 1012 molecules/cm3. Helium, methane, ethane, propane, and carbon monoxide were respectively introduced into the multi-pass cell to study their influences on the OH number density. The decay rate of OH number density was directly related to the reaction rates of the added gases. The low-pressure DBD OH multi-pass cell can be used as a reactor to further study the reaction kinetics associated with OH radicals.

中文翻译：

---

水蒸气介质阻挡放电产生低压OH自由基反应器

羟基 (OH) 自由基是通过介质阻挡放电 (DBD) 从体积为 8000 cm3 的多通道池中的水蒸气中产生的。在减压下用下列水蒸气填充电池。绝对 OH 数密度通过直接吸收光谱法使用可调谐激光器在 2.8 μm 处工作来准确确定。绝对 OH 数密度约为 1012 分子/cm3。将氦气、甲烷、乙烷、丙烷和一氧化碳分别引入多通道池中，研究它们对 OH 数密度的影响。OH数密度的衰减速率与添加气体的反应速率直接相关。低压 DBD OH 多通道池可用作反应器，以进一步研究与 OH 自由基相关的反应动力学。